The present invention is related generally to a noninvasive method and apparatus for characterizing biological materials and more particularly to a noninvasive method and apparatus for characterizing the state of biological materials in humans, animals and plants using scattered light. Examples of biological materials are bones and tissues in various parts and organs of the body of humans and animals including, the breasts, the eye, the lung, the heart, arteries and teeth and leafs of plants.
It is known to use spectrum information of scattered light as a means for detecting caries. In U.S. Pat. No. 4,479,499 to R. R. Alfano there is disclosed a method for detecting the presence of caries in the teeth of a person, the method involving radiating a region of the teeth to be examined with light; producing first and second signals corresponding to the intensity of the light scattered at first and second wavelength, respectively, the intensity of difference of the scattered light between caries and non-carious regions at said first wavelength being measurably different than the intensity difference of the scattered light between caries and non-carious regions at said second wavelength producing a third signal corresponding to the difference between said first and second signal; determining the value of said third signal when a known non-carious region is radiated; and detecting the presence of caries in other regions by said third signal changing from said value in a predetermined manner.
In U.S. Pat. No. 4,718,417 to Kittrell et al there is disclosed a method of distinguishing artery wall from atheromateous plaque which involves measuring the intensity of the fluorescence irradiated from the material over a plurality of wavelengths when excited by light.
The following publications are considered pertinent to this invention.
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It is an object of this invention to provide a new and improved method and apparatus for characterizing the state of biological materials in humans animals and plants.
It is another object of this invention to provide a method and apparatus as described above which is noninvasive.
It is yet still a further object of this invention to provide a method and apparatus as described above which involves the use of scattered light in angular and time regimes.
It is another object of this invention to provide a method and apparatus for characterizing the state of materials using backscattered light.
It is a further object of this invention to provide a method and apparatus as described above which involves the use of scattered light.
It is still a further object of this invention to provide a new and improved method and apparatus for measuring the scattering mean free path (1) and the absorption length (1a) of light scattering in random materials.